Differential Pulse Adsorption Stripping Voltammetric Determination of Copper(II) with 2-Mercaptobenzimidazol at a Hanging Mercury-Drop Electrode

Copper(II) was selectively accumulated on a hanging mercury-drop electrode by using 2-mercaptobenzimidazole. Ensuing measurements were carried out by differential pulse adsorption stripping voltammetry. Factors affecting the accumulation, reduction, and stripping steps were investigated and a procedure was developed. The optimum conditions for the analysis of copper were pH 5.0, 5.33 × 10–5 M 2-mercaptobenzimidazole and an accumulation potential of–0.10 V (vs. Ag/AgCl). A linear range was obtained in the concentration range 0.2–100 ng/ml with a 90 s accumulation time and a scan rate of 16 mV/s. For ten successive determinations of 1.0, 20.0 and 70.0 ng/ml copper(II), relative standard deviations of 4.2, 3.5 and 2.8%, respectively, were obtained. The developed method was applied to the determination of copper in commercial salts and aluminium alloys.